Brake head and shoe assembly



A ril 24, 1934. T. K. CUMMINS BRAKE HEAD AND SHOE ASSEIBLY Filed May 12. 1933 INVENTOR. THOMAS K.CUMMINS M, 4 WM .4 TTORNEYS.

Patented Apr. 24, 1934 UNITED STATES PATENT OFFICE BRAKE HEAD AND SHOE ASSEMBLY Application'May 12, 1933, Serial No. 670,694

8 Claims.

This invention relates to improvements in brake head and shoe assemblies and has for its principal object to reduce to a minimum the wear between the connecting lugsof the head and shoe.

These heads are usually made of a relatively soft metal, such as malleable iron, and the shoes are made of harder metal. It is thepractice to allow suflicient clearance between the head and shoe and lugs thereof to permit the shoe to adjust itself to the wheel, and also to slight differences in the assembly and relations of the parts. As the result of this arrangement, there is a comparatively large amount of vibration and hammering between the lugs which, because of the rela- 16 tive softness of the metal of the shoe lug, results in rapid wear of the head lugs. This necessitates frequent replacement and corresponding maintenance expense.

Various devices for overcoming this wear have been tried. For example, different forms of keys have been used to reduce vibration. Wedges have been used to substantially prevent, or reduce to a minimum, the movements between the parts but these devices are all unsatisfactory particularly those that prevent the proper degree of adjusting motions between the parts.

The present invention allows of proper adjustment of the shoe, yet reduces wear to a minimum by providing a hardened metal insert as a buffer, arranged on or in one head lug in a manner to support or be engaged by a surface of the lug of the shoe.

Features of the invention include: the use of a hard metal insert or a plurality of such inserts as buffer and anti-wear means against which the lug of the shoe engages; the provision of means for pocketing or socketing such an insert; the provision of a recess in the head lug of a character which receives the insert as well as a portion of the shoe lug; the formation of means for guiding the insertion of the metal insert; the proportioning of the wear insert and recess therefor so that the insert is secured by a driving fit; the use of peening as a means for securing the insert in operative position against disengagement; the making of the insert from hard unfracturable metal material; the making of the insert from case hardened mild steel; the making of the insert from laminated steel; the reenforcement of the lugs; and generally to all details of construction relating to the anti-wear and buffer assembly.

Objects, features and advantages of the invention will be set forth he description of the drawing forming a part oi this application, and in said drawing.

Figure '1 is a side elevation partly in section 11- lustrating the assembly relations of the insert to head and shoe; 7

Figure 2 is a fragmentary elevation of the lug of the head viewed from the inner side and showing the guides for the recess;

Figure 3 is a horizontal section on line 3-3 of Figure 1, showing the relation of the recesses to the insert and the method of securing the same by peening;

Figure 4 is a perspective view of the preferred form of insert;

Figure 5 is a vertical section on line 5-5 of Figure 3 illustrating the reenforcing structure for the head lug; and v Figure 6 is a fragmentary vertical section corresponding to Figure 1, illustrating the application of inserts one to each of the head lugs.

Numeral 1 generally indicates the head formed from the usual relatively soft metal and having the usual means generally indicated at 2 by which it is attached to the brake beam, and further having the usual hanger openings 3, 4, 5, for the usual suspending links. The inner face of the head 1 provides at its upper and lower extremities recesses 7-8 which herein have the form of slots opening toward the shoe. Between the link openings 4 and 5 at the inner face of the head is arranged an apertured or hollow lug 9, and spaced from this lug and also extending from the inner face of the head is an apertured lug 10. The particular construction of the lug 10 is also a feature of this invention. It will be understood, of course, that the lug 9 may have the same construction, see Figure 6.

The lug 10 is formed in this instance by casting to provide (see Figures 1 and 3) an outer recess 11, and an inner recess 12, the recesses being intercommunicating. The metal of the lug bulges laterally, as shown, and is formed to provide guides 13 into which the metal buffer 14 is imserted. By this means, the shoe-lug-engaging surface of the insert lies at a level below the upper surface of the lug and provides a pocket 15 for the reception of the lower portion of the lug of the shoe.

The metal insert has herein the form of a plate provided at the rear with a longitudinal extension 16 which fits into the recess 12. The plate is beveled at each front corner as at 17, and has an aperture 18 for traversal by the key. The dimensions of the recess 11 and of the plate 14 are such that it is necessary to drive the bufl'er plate into the position shown in Figure 3. After driving the plate to the position shown, the outer portions of the guide-forming portions of the lug are peened as at 19 to the position shown in Figure 3, to secure the plate in operative position. .The front portions of the guides above the plate are beveled as at 20.

It is important that the wear plate be securely fixed so that it will not become loosened by the violent hammering between it and the lower surface of the lug 21 of the shoe 22.

The wear plate is made from hard unfracturable steel or steel-faced material, or from steel which is case hardened, or from laminated or three-ply steel which comprises outer hard steel facings enclosing a softer steel core. It is not desirable to use spring steel because, if it is' not properly tempered, it may fracture under the; hammer blows of the shoe lug.

The attachment of the shoe to the head is made so that the outer extremities of the shoe are slightly spaced from the corresponding extremi ties 25-26 of the head. The key 27' is generally driven, and is so applied that it acts on the inner walls 0! the tubular lugs to draw the middle portion of the shoe into contact with the faces of the lugs 9 and 10. In this way the shoe can rock in a vertical plane against the springing action of the key. As shown in Figures 1 and 6. the front and rear walls of the plate aperture 18 are substantially flush with the corresponding inner walls of the lug apertures. Although an opening 18 is provided in the plate. the plate could as well be slotted inwardly through the portion 16. There is no limitation intended in regard to the formation of the plate for permitting traversal by the key. The hollow lugs 9 and 10 are each reenforced as at 28, see Figures 1 and 5, by substantially increasing the metal thickness vertically, as well as horizontally and transversely.

I claim as my invention:

1. In combination, a brake head having spaced apertured lugs, a brake shoe having an apertured lug operatively arranged between the first mentioned lugs, one of said head lugs having a recess, and an anti-wear plate forming the bottom of the recess and supporting the shoe lug, and a key traversing the lugs and operably securing the shoe to the head.

2. A head having upper and lower spaced apertured lugs, the lower lug having a recess, an antiwear element in the recess, a brake shoe having an apertured lug operably arranged between the first mentioned lugs and entering the recess and en aging said wear plate, and a key traversing Zhe lugs and operably securing the shoe to the ead.

3. In combination, a brake head having spaced apertured lugs, a shoe having an apertured lug operatively arranged between the first mentioned lugs, one of said first mentioned lugs having a recess having oppositely facing grooves, an anti-wear element having a driven fit with the recess and forming the bottom thereof, and supporting the shoe lug, and a key traversing the lugs and operably securing the shoe to the head.

4. In combination a brake head having spaced apertured lugs, one of the lugs having outer and inner recesses, an anti-wear element arranged in the outer recess and having a projection which enters the inner recess, means securing said elsment in the recess, a brake shoe having an apertured lug operably arranged between the first mentioned lugs and resting on said anti-wear element, and a key traversing the lugs and operably securing the shoe to the head.

5. In combination, a brake head having spaced apertured lugs, one of the lugs having a recess providing guides, an anti-wear element having portions entering and held in the guides, said portions of said element having bevels, the metal of the guides being bent against said bevels to secure the element in the guides, a brake shoe having an apertured lug operably arranged between the first mentioned lugs and resting .on said element, and a key traversing the lugs and operably securing the shoe to the head.

. 6. A brake head having a shoe-lug-supporting lughaving an upwardly opening recess of an area to receive the lug of a shoe, said recess having therein opposed guide grooves one adjacent each lateral face of the lug, and an antiwear brake-shoe-lug-supporting plate having a sliding fit'in the grooves and forming the bottom of the recess.

'1. A brake head having a shoe-lug-supporting lug having an upwardly opening recess, said recess having a groove in each of two opposite lateral walls, an anti-wear brake-shoe-lug-supporting plate having a sliding fit in the grooves and means securing the plate in said grooves.

8. A brake head having 9. lug having in its upper surface an upwardly opening recess of an area sufiicient to receive the lug oi a brake shoe, and an anti-wear plate held in said recess and forming the bottom thereof and having an opening through which a key can pass to secure the lugs of head and shoe in operative relation.

THOMAS K. CUMIHINS. 

